Re: [boost] Revised boost.python nested class patch

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-12-16 23:49:48

Scott,

It looks like you are making (very!) sensible changes here. It would be
easier for both of us if I gave you CVS write access. If you're interested,
please (aquire, if neccessary, and) send me a SourceForge UserID. I suggest
"scott_snyder" if you don't have one and it's available.

-Dave

----- Original Message -----
From: "scott snyder" <snyder_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Sunday, December 16, 2001 9:54 PM
Subject: [boost] Revised boost.python nested class patch

>
> hi -
>
> Here's a revised version of this patch that adds test code and
> a mention in the documentation.
>
> This just allows you to specify another class_builder as the first
> argument of a class_builder constructor, in order to make a class be
> an attribute of another class.
>
> sss
>
>
> Index: boost/python/class_builder.hpp
> ===================================================================
> RCS file: /cvsroot/boost/boost/boost/python/class_builder.hpp,v
> retrieving revision 1.3
> diff -u -p -r1.3 class_builder.hpp
> --- boost/python/class_builder.hpp 2001/03/03 12:55:53 1.3
> +++ boost/python/class_builder.hpp 2001/12/16 21:08:16
> @@ -25,6 +25,22 @@ class class_builder
>          module.add(ref(as_object(m_class.get()), ref::increment_count),
name);
>      }
>
> +  template <class OtherT, class OtherU>
> +    class_builder(class_builder<OtherT, OtherU>& cls, const char* name)
> +        : m_class(new detail::extension_class<T, U>(name))
> +    {
> +        cls.add(ref(as_object(m_class.get()), ref::increment_count),
name);
> +    }
> +
> +  template <class OtherT, class OtherU>
> +    class_builder(detail::extension_class<OtherT, OtherU>* cls,
> +                  const char* name)
> +        : m_class(new detail::extension_class<T, U>(name))
> +    {
> +        cls->set_attribute(name,
> +                           ref(as_object(m_class.get()),
ref::increment_count));
> +    }
> +
>      ~class_builder()
>      {}
>
> Index: libs/python/doc/exporting_classes.html
> ===================================================================
> RCS file: /cvsroot/boost/boost/libs/python/doc/exporting_classes.html,v
> retrieving revision 1.1
> diff -u -p -r1.1 exporting_classes.html
> --- libs/python/doc/exporting_classes.html 2001/03/07 03:39:31 1.1
> +++ libs/python/doc/exporting_classes.html 2001/12/16 21:08:16
> @@ -98,6 +98,11 @@ Notes:<ul>
>
>  <li>Any function added to a class whose initial argument matches the
class (or
>  any base) will act like a member function in Python.
> +
> +<li>The first argument to the <tt>class_builder</tt> constructor
> +may be another <tt>class_builder</tt> instance, as well as a
> +<tt>module_builder</tt>.  This defines a nested class, as you'd expect.
> +
>  </ul>
>        <p>
>           We can even make a subclass of <code>hello.world</code>:
> Index: libs/python/test/comprehensive.cpp
> ===================================================================
> RCS file: /cvsroot/boost/boost/libs/python/test/comprehensive.cpp,v
> retrieving revision 1.14
> diff -u -p -r1.14 comprehensive.cpp
> --- libs/python/test/comprehensive.cpp 2001/12/16 17:58:23 1.14
> +++ libs/python/test/comprehensive.cpp 2001/12/16 21:08:16
> @@ -67,6 +67,16 @@ Foo::PythonClass::PythonClass(boost::pyt
>      def(&Foo::add_len, "add_len", &FooCallback::default_add_len);
>
>      // Since pure() is pure virtual, we are leaving it undefined.
> +
> +    // And the nested classes.
> +    boost::python::class_builder<Foo::Foo_A> foo_a(*this, "Foo_A");
> +    foo_a.def(boost::python::constructor<>());
> +    foo_a.def(&Foo::Foo_A::mumble, "mumble");
> +
> +    boost::python::class_builder<Foo::Foo_B> foo_b(get_extension_class(),
> +                                                   "Foo_B");
> +    foo_b.def(boost::python::constructor<>());
> +    foo_b.def(&Foo::Foo_B::mumble, "mumble");
>  }
>
>  BarPythonClass::BarPythonClass(boost::python::module_builder& m)
> @@ -221,6 +231,16 @@ IntPair make_pair(int x, int y)
>  const char* Foo::mumble()
>  {
>      return "mumble";
> +}
> +
> +const char* Foo::Foo_A::mumble()
> +{
> +    return "mumble a";
> +}
> +
> +const char* Foo::Foo_B::mumble()
> +{
> +    return "mumble b";
>  }
>
>  void Foo::set(long x)
> Index: libs/python/test/comprehensive.hpp
> ===================================================================
> RCS file: /cvsroot/boost/boost/libs/python/test/comprehensive.hpp,v
> retrieving revision 1.2
> diff -u -p -r1.2 comprehensive.hpp
> --- libs/python/test/comprehensive.hpp 2000/11/27 07:23:15 1.2
> +++ libs/python/test/comprehensive.hpp 2001/12/16 21:08:16
> @@ -42,6 +42,10 @@ class Foo                // prohibit cop
>      std::string call_pure();                    // call a pure virtual
fuction
>      int call_add_len(const char* s) const;      // virtual function with
a default implementation
>
> +    // A couple nested classs.
> +    struct Foo_A { const char* mumble(); };
> +    struct Foo_B { const char* mumble(); };
> +
>   private:
>      // by default, sum the held value and the length of s
>      virtual int add_len(const char* s) const;
> Index: libs/python/test/comprehensive.py
> ===================================================================
> RCS file: /cvsroot/boost/boost/libs/python/test/comprehensive.py,v
> retrieving revision 1.13
> diff -u -p -r1.13 comprehensive.py
> --- libs/python/test/comprehensive.py 2001/12/15 22:59:48 1.13
> +++ libs/python/test/comprehensive.py 2001/12/16 21:08:16
> @@ -230,6 +230,14 @@ Polymorphism also works:
>      >>> baz.get_foo_value(polymorphic_foo)
>      1000
>
> +Simple nested class test:
> +    >>> foo_a = Foo.Foo_A()
> +    >>> foo_a.mumble()
> +    'mumble a'
> +    >>> foo_b = Foo.Foo_B()
> +    >>> foo_b.mumble()
> +    'mumble b'
> +
>  Pickling tests:
>
>      >>> world.__module__
>
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